1. Field of the Invention
The present invention relates to a method used in a wireless communication system and related communication device, and more particularly, to a method of handling a control channel and related communication device.
2. Description of the Prior Art
A long-term evolution (LTE) system supporting the 3GPP Rel-8 standard and/or the 3GPP Rel-9 standard are developed by the 3rd Generation Partnership Project (3GPP) as a successor of a universal mobile telecommunications system (UMTS), for further enhancing performance of the UMTS to satisfy increasing needs of users. The LTE system includes a new radio interface and a new radio network architecture that provides a high data rate, low latency, packet optimization, and improved system capacity and coverage. In the LTE system, a radio access network known as an evolved universal terrestrial radio access network (E-UTRAN) includes multiple evolved Node-Bs (eNBs) for communicating with multiple UEs, and communicating with a core network including a mobility management entity (MME), a serving gateway, etc., for Non-Access Stratum (NAS) control.
A LTE-advanced (LTE-A) system, as its name implies, is an evolution of the LTE system. The LTE-A system targets faster switching between power states, improves performance at the coverage edge of an eNB, and includes advanced techniques, such as carrier aggregation (CA), coordinated multipoint transmission/reception (CoMP), UL multiple-input multiple-output (MIMO), etc. For a UE and an eNB to communicate with each other in the LTE-A system, the UE and the eNB must support standards developed for the LTE-A system, such as the 3GPP Rel-10 standard or later versions.
Thus, a large amount of control information is needed to realize the abovementioned systems. Accordingly, advanced control channels are introduced for transmitting the control information, e.g., enhanced physical control format indicator channel (EPCFICH), enhanced physical downlink control channel (EPDCCH). Different from a legacy physical downlink control channel (PDCCH) which can only be transmitted in first few orthogonal frequency domain multiplexing (OFDM) symbols of a subframe, the advanced control channels can be transmitted in more symbols to achieve flexibility and robustness. As a result, the eNB needs to indicate (i.e., configure) the advanced control channels to the UE by using a larger amount of signaling. Thus, how to indicate the advanced control channels efficiently is an important topic to be discussed. That is, the eNB indicate the EPDCCH to the UE by using a signaling with low overhead, while the UE can still detect (e.g., locate, detect) and recover the EPDCCH correctly according to the signaling.